The present disclosure relates generally to an acceleration system for generating monoenergetic protons. The present disclosure relates more particularly to an acceleration system for generating monoenergetic protons that has a sufficient acceleration gradient to achieve a compact system. Oncology or cancer treatment using energetic protons is a well-established approach to treatment due to the favorable ballistic and range properties of proton beams. The advantage of proton therapy lies in a pronounced peak, known in the art as Bragg's peak, of energy loss of ionizing radiation along the path of the accelerated protons. Physicians can precisely deliver the radiation dose to the target and greatly reduce the damage to normal cells and tissues. However, major problems of the current sources of energetic protons used in cancer therapy are cost and the large size of the installation. At present, conventional proton therapy centers can cost from $100M to $200M due to the size and complexity of the existing proton generating technology. Currently available cyclotron accelerator-based proton therapy systems are large and cost ˜$150 million. Currently available synchrotron based proton accelerators are expensive (costing >$100 million each) and occupy a larger space than can fit into a standard room in a building, making it nearly impossible to install in a community hospital and generalize its usage.
Another disadvantage to currently available proton therapy systems is that the minimum size of the beam spot of the delivered energy is limited to millimeter, which lacks precision for intricate treatments.
One possible source of laser proton therapy, Target Normal Sheath Acceleration (TNSA) with laser radiation on thick targets of thickness>laser wavelength to produce energetic protons, has proven unsuitable for medical applications because the energy spectrum is broad, few protons reach the maximum energy, the efficiency of energy conversion to energetic protons is low. A >1 Peta-Watt laser source is required to achieve 60 MeV protons, even with a low quality proton beam having large energy spread.